Again allow comment header in JSON for NSX

go/pkg/nsx/parse.go

@@ -1,6 +1,7 @@
 package nsx
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 
@@ -112,7 +113,7 @@ func (s *State) ParseConfig(data []byte, fName string) (
 	if len(data) == 0 {
 		return config, nil
 	}
-	err := json.Unmarshal(data, config)
+	err := json.Unmarshal(removeHeader(data), config)
 	if err != nil {
 		return nil, err
 	}
@@ -136,3 +137,17 @@ func checkConfigValidity(c *NsxConfig) error {
 	}
 	return nil
 }
+
+func removeHeader(data []byte) []byte {
+	for {
+		if bytes.HasPrefix(data, []byte("#")) {
+			i := bytes.IndexByte(data, byte('\n'))
+			if i == -1 {
+				return data[len(data):]
+			}
+			data = data[i+1:]
+		} else {
+			return data
+		}
+	}
+}

go/testdata/nsx.t

@@ -833,15 +833,34 @@ ERROR>>> While reading router: invalid character 'i' looking for beginning of ob
 ############################################################
 =TITLE=Invalid JSON from device
 =DEVICE=
-# Some comment
-[[one_rule]]
+#Good
+
+#Bad
 =NETSPOC=
-Generated by Netspoc devel
 [[one_rule]]
 =ERROR=
 ERROR>>> While reading device: invalid character '#' looking for beginning of value
 =END=
 
+############################################################
+=TITLE=Remove comment header from file
+=DEVICE=
+#Some comment
+# More
+# lines follow
+[[one_rule]]
+=NETSPOC=
+[[one_rule]]
+=OUTPUT=NONE
+
+############################################################
+=TITLE=File with only comment header
+=DEVICE=# Some comment
+=NETSPOC={}
+=ERROR=
+ERROR>>> While reading device: unexpected end of JSON input
+=END=
+
 ############################################################
 =TITLE=Patch existing Service
 # Remove source_ports from service